People who are busy or traveling can have great difficulty contacting each other by telephone. A person can be at several locations during the day, each of which can be reached only by a telephone line unique to that location. Messages can be left, but by the time the recipient receives the message the caller may have moved on to a new location and can no longer be reached at the phone number indicated in the message. This is commonly called "phone tag". In addition, the person receiving the call may not want to be disturbed at that time, or may want to hear from certain people rather than others.
Several solutions to the problem of phone tag are known. One such solution is to use cellular telephones which allow a single telephone number to relocate with the subscriber. However cellular telephones are limited by service area and are not affordable to the average subscriber. Another known solution is call forwarding service which can be used to forward calls to the recipient's present location, but blindly forwards all calls irrespective of who the caller is or whether the called person is ready to receive a call at that time. Call forwarding must also be updated through the subscriber's primary phone line as the subscriber moves from location to location.
U.S. Pat. No. 5,315,636 presents a yet further solution in which a subscriber carries a small communication device that alerts a nearby base station as to the subscriber's location. When the subscriber receives an incoming call the service consults a lookup table to determine the phone line that the subscriber has associated with that base station. The disadvantage of this solution is that special hardware is needed at various locations. The subscriber is also unable to prioritize callers or selectively block out certain callers.
An alternative solution to the phone tag problem is desired.